The municipality includes the following zones: San Carlos, El Tesoro, La Barra, Edén Rock, El Chorro, Manantiales, Balneario Buenos Aires, Punta Piedras, Santa Mónica, San Vicente [es], El Edén, Paso de la Cantera, Las Cañas, Carapé, Mataojo, Guardia Vieja, Pago de la Paja, Partido Norte, Partido Oeste, Cañada Bellaca, Corte de la Leña, Punta del Campanera, Puntas de Mataojo, and Laguna José Ignacio.

The stream Arroyo San Carlos flows along the east limits of the city and the park and neighbourhood of Parque Medina is situated across it.

It was founded on October 1763 by the Spanish Governor Pedro Antonio de Cevallos, to discourage the foundation of Portuguese settlements in the region.

It had acquired the status of "Villa" (town) before the Independence of Uruguay, which was elevated to "Ciudad" (city) on 18 December 1929 by the Act of Ley Nº 8.559.

According to the Intendencia Departamnetal de Maldonado, the municipality of San Carlos has a population of 27,000.